From 405489769eb1192920525dca698df508df77b98f Mon Sep 17 00:00:00 2001
From: ekeeke31 <ekeeke31@fcb46045-4337-0410-a722-cd382f7ce8f6>
Date: Tue, 16 Jun 2009 17:00:40 +0000
Subject: [PATCH] ~modified default 68k mapped memory (VDP DMA accesses WRAM
 only above $800000)

---
 source/cart_hw/cart_hw.c | 5 +++--
 source/genesis.c         | 8 +++++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/source/cart_hw/cart_hw.c b/source/cart_hw/cart_hw.c
index 8ef5fed..09aa254 100644
--- a/source/cart_hw/cart_hw.c
+++ b/source/cart_hw/cart_hw.c
@@ -163,7 +163,7 @@ void cart_hw_init()
   ***********************************************/
   for (i=0; i<0x40; i++)
   {
-      /* cartridge ROM */
+    /* cartridge ROM */
     m68k_memory_map[i].base     = cart_rom + (i<<16);
     m68k_memory_map[i].read8    = NULL;
     m68k_memory_map[i].read16   = NULL;
@@ -175,7 +175,8 @@ void cart_hw_init()
 
   for (i=0x40; i<0x80; i++)
   {
-      /* unused area */
+    /* unused area */
+    m68k_memory_map[i].base     = cart_rom + (i<<16);
     m68k_memory_map[i].read8    = m68k_read_bus_8;
     m68k_memory_map[i].read16   = m68k_read_bus_16;
     m68k_memory_map[i].write8   = m68k_unused_8_w;
diff --git a/source/genesis.c b/source/genesis.c
index 7e64db1..7c849e8 100644
--- a/source/genesis.c
+++ b/source/genesis.c
@@ -53,8 +53,10 @@ void gen_init (void)
   m68k_init();
   z80_init(0,0,0,z80_irq_callback);
 
-  /* initialize 68k default address space */
-  for (i=0x0; i<0x100; i++)
+  /* initialize 68k mapped memory */
+  /* $000000-$7fffff is affected to cartridge area (see cart_hw.c) */
+  /* $800000-$ffffff is affected to WRAM (see VDP DMA) */
+  for (i=0x80; i<0x100; i++)
   {
     m68k_memory_map[i].base     = work_ram;
     m68k_memory_map[i].read8    = NULL;
@@ -65,7 +67,7 @@ void gen_init (void)
     zbank_memory_map[i].write   = NULL;
   }
 
-  /* initialize 68k memory map */
+  /* initialize 68k memory handlers */
   for (i=0x80; i<0xe0; i++)
   {
     /* illegal area */